support/kconfig/merge_config.sh: avoid false positive matches from comment lines

We are using empty CONFIG_PREFIX_. This results in false positive match
for comment lines when merging config fragments.

To avoid false positive reports, we use separate sed expressions and
address comment lines explicitly.

This is actually is in the Linux kernel mainline (v4.20-rc2):
6bbe4385d035c6fac56f840a59861a0310ce137b
("kconfig: merge_config: avoid false positive matches from comment lines")

Signed-off-by: Nasser Afshin <Afshin.Nasser@gmail.com>
Reviewed-by: Petr Vorel <petr.vorel@gmail.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

support/kconfig/merge_config.sh

@@ -109,7 +109,8 @@ if [ ! -r "$INITFILE" ]; then
 fi
 
 MERGE_LIST=$*
-SED_CONFIG_EXP="s/^\(# \)\{0,1\}\(${CONFIG_PREFIX}[a-zA-Z0-9_]*\)[= ].*/\2/p"
+SED_CONFIG_EXP1="s/^\(${CONFIG_PREFIX}[a-zA-Z0-9_]*\)=.*/\1/p"
+SED_CONFIG_EXP2="s/^# \(${CONFIG_PREFIX}[a-zA-Z0-9_]*\) is not set$/\1/p"
 
 TMP_FILE=$(mktemp -t .tmp.config.XXXXXXXXXX)
 
@@ -123,7 +124,7 @@ for MERGE_FILE in $MERGE_LIST ; do
 		echo "The merge file '$MERGE_FILE' does not exist.  Exit." >&2
 		exit 1
 	fi
-	CFG_LIST=$(sed -n "$SED_CONFIG_EXP" $MERGE_FILE)
+	CFG_LIST=$(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $MERGE_FILE)
 
 	for CFG in $CFG_LIST ; do
 		grep -q -w $CFG $TMP_FILE || continue
@@ -166,7 +167,7 @@ make KCONFIG_ALLCONFIG=$TMP_FILE $EXTERNAL_ARG $OUTPUT_ARG $ALLTARGET
 
 
 # Check all specified config values took (might have missed-dependency issues)
-for CFG in $(sed -n "$SED_CONFIG_EXP" $TMP_FILE); do
+for CFG in $(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $TMP_FILE); do
 
 	REQUESTED_VAL=$(grep -w -e "$CFG" $TMP_FILE)
 	ACTUAL_VAL=$(grep -w -e "$CFG" "$KCONFIG_CONFIG")

support/kconfig/patches/21-Avoid-false-positive-matches-from-comment-lines.patch

@@ -0,0 +1,32 @@
+Index: kconfig/merge_config.sh
+===================================================================
+--- kconfig.orig/merge_config.sh
++++ kconfig/merge_config.sh
+@@ -109,7 +109,8 @@ if [ ! -r "$INITFILE" ]; then
+ fi
+ 
+ MERGE_LIST=$*
+-SED_CONFIG_EXP="s/^\(# \)\{0,1\}\(${CONFIG_PREFIX}[a-zA-Z0-9_]*\)[= ].*/\2/p"
++SED_CONFIG_EXP1="s/^\(${CONFIG_PREFIX}[a-zA-Z0-9_]*\)=.*/\1/p"
++SED_CONFIG_EXP2="s/^# \(${CONFIG_PREFIX}[a-zA-Z0-9_]*\) is not set$/\1/p"
+ 
+ TMP_FILE=$(mktemp -t .tmp.config.XXXXXXXXXX)
+ 
+@@ -123,7 +124,7 @@ for MERGE_FILE in $MERGE_LIST ; do
+ 		echo "The merge file '$MERGE_FILE' does not exist.  Exit." >&2
+ 		exit 1
+ 	fi
+-	CFG_LIST=$(sed -n "$SED_CONFIG_EXP" $MERGE_FILE)
++	CFG_LIST=$(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $MERGE_FILE)
+ 
+ 	for CFG in $CFG_LIST ; do
+ 		grep -q -w $CFG $TMP_FILE || continue
+@@ -166,7 +167,7 @@ make KCONFIG_ALLCONFIG=$TMP_FILE $EXTERN
+ 
+ 
+ # Check all specified config values took (might have missed-dependency issues)
+-for CFG in $(sed -n "$SED_CONFIG_EXP" $TMP_FILE); do
++for CFG in $(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $TMP_FILE); do
+ 
+ 	REQUESTED_VAL=$(grep -w -e "$CFG" $TMP_FILE)
+ 	ACTUAL_VAL=$(grep -w -e "$CFG" "$KCONFIG_CONFIG")

support/kconfig/patches/series

@@ -9,3 +9,4 @@
 18-merge-config.sh-create-temporary-files-in-tmp.patch
 19-merge_config.sh-add-br2-external-support.patch
 20-merge_config.sh-Allow-to-define-config-prefix.patch
+21-Avoid-false-positive-matches-from-comment-lines.patch